patch 8.2.3620: memory leak reported in libtlib

Problem:    Memory leak reported in libtlib.
Solution:   Call del_curterm() when cleaning up memory.  Rename term.h to
            termdefs.h to avoid a name clash.

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3620,
 /**/
     3619,
 /**/